POOR DRIVEABILITY/PERFORMANCE INCORRECT GAS/DIESEL CAMSHAFT

VEHICLES AFFECTED: 1981 - 1985 'G', 'B', and 'E' 1981 - 1984 'C'

Roller lifter camshafts for 1981-85 V8 diesel and 1985 and later V8 gasoline engines are almost identical except for lobe contour and their fit to the camshift adapter. Until recently it was impossible to inadvertently install the wrong camshaft in an engine because:

- The adapter on a diesel engine is smaller and will not fit a gas camshaft.

- The adapter on a gas engine contains a pin that must fit into a hole. This hole is not drilled on a diesel camshaft.

Shortly this pin will be removed from the gas adapter. It would then be possible to inadvertently install a diesel camshaft in a gas engine. This will result in poor performance and economy due to cam lobe contour differences.

Identification:

--------------- There is .38mm (.015 in.) difference between the adatper hole size. A gasoline adapter on a diesel camshaft will have a very sloppy fit. The diameter of the camshaft where it fits to the adapter is:

Gasoline - 24.16mm - 24.18mm (.951 in. - .952 in.) Diesel - 23.77mm - 23.80mm (.936 in. - .937 in.)

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.